Method of casting products embodying material of low specific gravity



March 22, 19 2- D. s. CONNEILLY ET AL 1,850,743

METHOD OF CASTING PRODUCTS EMBODYING MATERIAL OF LOW SPECIFIC GRAVITYFiled March 25. 1931 Jwuantow p. a comgzg Z J Hal/212 Patented Mar. 22,1932 UNITED STATES PATENT OFFICE DONALD S. GONNELLY, OF WOOSTEB, ANDTHEODORE I. HA ER, OF CARTON, OHIO, .AS-

SIGNOBS 1'0 WOOB'I'ER PRODUCTS INC, 01' WOOSTEB, OHIO, A CORPORATION OFOHIO METHOD OF CASTING .ZPBODUCTS monme LOW SPECIFIC GRAVITY Applicationmm ma a5, 1931. semi 110. 525,128.

The invention relates to a method of producing' cast bodies bodilyincorporating zones of relatively low specific gravity material.

5 More particularly, the invention relates to a method of producing castmetal stair treads, embodying segregations of comminuted abrasive orwear-resistant material.

Stair treads which are in common use are usually provided with a coatingor wearing surface of abrasive or wear-resistant material. A commonmethod of producing such stair treads is to sprinkle the surface of themold in which the tread is to be cast with comminuted resistantmaterial, spray the resistant material with a suitable binder, and thenpour the casting.

Stair treads produced by this method however, present a wear-resistantcoating, the

particles of which are rapidly dislodged or =worn 0E in use, and themore or less pure cast metal next encountered does not possess thenecessary frictional and wear-resistant qualities.

Itis therefore desirable to provide a cast stair tread containingcomminuted wear-resistant material distributed throughout the same, buta satisfactory method of making the same has not, to our knowledge. beenthat when the molten metal is poured into the mold, wear-resistantmaterial which is free to move, will rise to the top of the mold becauseof its relatively low specific gravity.

Accordingly, it is an object of the present invention to provide amethod of producing a casting having comminuted abrasive orwear-resistant material substantially segregated at desired zones in thecasting.

Another object is to provide for substantially restricting the flow ofand segregating the comminuted material during the casting operation, byemploying a medium of such character that the same will becomesubstantially fused and merged with the cast metal when the latter hasbecome chilled.

, A- still further object is to provide a method of producing a castinghaving commi- 50 nuted abrasive or wear-resistant material known in thepast. The difiiculty arises in' lsrlplstantially distributed throughoutthe cast These and other objects are attained by the improved methodcomprisin the present invention, as will be hereina er pointed out indetail. 7

In general terms, the invention consists in sp abrasive orwear-resistant material over the bottom surface of the mold cavity inwhich the product is to be cast, spraying said abrasive material with asuitable binder, suspending a preferably perforated plate adhesivelycoated with abrasive or wear-resistant material in the mold cavity inspaced preferably parallel relation to said bottom surface thereof,anchoring said plate against displacement, and pouring molten metal intothe mold cavity.

A. preferred embodiment of the present invention is illustrated in theaccompanying drawings, in which Figure 1, is a fragmentary crosssectional view of a mold prior to the casting of the product therein,showing a plate coated with abrasiveior wear-resistant materialsuspended in the mold cavity;

Fig. 2 is a detached fragmentary tive view of the plate partially coatedwith abrasive on wear-resistant material; and

Fig. 3 is a. fragmentary cross sectional view of the finished product. i

Similar numerals refer to similar parts throughout the drawings.

The invention may be carried out by employing an ordinary mold as shownin Fig.

1, having the cope 10 and the drag 11. The

mold cavity 12 is preferably located in the drag as shown, and has inletand outlet gates 13 and 14 respectively, communicating with the ends ofthe mold cavity.

The cope may be provided with a pouring sprue 15, communicating with thegate 13, and with a riser 16 communicating with the gate 14.

One or more plates, which may be approximately 28 gauge, low carbonsteel, are provided for accomplishing segregation of the abrasive orwear-resistant material within the cast product. For convenience, oneplate 17 is shown in the drawings.

the body of the This plate is preferably perforated as shown, andadapted to be anchored against displacement in the mold cavity duringcasting. Before insertion into the mold cavity, however, the plate 17 isthoroughly coated on all surfaces with comminuted abrasive orwear-resistant material asindicated at 18, such as carborundum, whichmay be applied by using asuitable adhesive, such as asphaltum adhesivematerial.

The fusing point of the plate 17 is preferably'lower than that of themetal constituting casting, which metal may be cast iron, so that duringthe casting operation, said plate will become substantially entirelyfused and merged with the molten metal.

If desired, a fusible adhesive material, such as sodium silicate, may beused for coating the plate 17 with carborundum, so that when the castingis poured the adhesive will fuse with the molten metal.

The plate 17 may be anchored in the mold cavity immediately adjacent thebottom surface thereof, or suspended and anchored in the cavity inspaced relation to said bottom surface, as shown in Fig. 1. This may beaccomplished by any convenient means, as by punching tangs 20 out of theplate for contacting with the cope of the moldto properly space theplate therefrom; and by providing holes 21 in the plate 17, throughwhich foundry nails 22 may be driven into the cope for securing theplate thereto against displacement during the casting operation.

Preferablythe plate 17 is of such dimensions as to have its ends spacedfrom the ends of the mold cavity, as shown at 23 and 24, when the plateis positioned in the. mold cavity. I

If a plurality of plates 17 are used they may be suspended and anchoredin a similar manner at vertically spaced lntervals in the cavity.

Tn carrying out the invention, the mold cavity 12 is formed in the drag11 in the usual manner. The bottom surface 12- of the cavity 12 is thensprayed with a suitable binder such as asphaltum binder and the like,and comminuted abrasive material, which may be carborundum, is sprinkledover the sprayed bottom surface as indicated at 18. The bottom of themold cavity covered withthe comminuted carborundum is again sprayed withthe asphaltum binder. i

The plate 17 adhesively coated with abrasive or wear-resistant materialis then secured to the underside of the cope, in a man' relation to thebottom surface 12 of the ner previously described. The cope is placed inposition on the drag, andthe plate 17 is thus suspended in spacedpreferably parallel mold cavity, and has its ends spaced from the endsof the mold cavity.

The molten'metal is then poured through and allowed to chill.

When the molten metal enters-the molten cavity through the gate 13, itfirst flows under the plate '17 and over the bottom of the mold cavity.As the binder holding the abrasive material 18 to the bottom 12 becomesgasified, some of the particles of the abrasive will befreed and beginto rise, due to their relatively low specific gravity.

As the molten metal rises to the region or zone of the adhcsively coatedplate 17, its heat will also act upon the adhesive material holding thecomminuted abrasive material 18 to the plate, to liberate some of theparticles of the abrasive material 18.

Since the plate 17 is secured to the cope against bodily displacement,the pressure of the molten metal upon the underside of the plate 17would ordinarily tend to warp the plate, but theperforations permit someof the molten metal to be forced up throughthe plate, with the resultthat any substantial warping of the plate is obviated.

It will be understood that since the metal plate 17 is relatively cold,its effect will be to chillthe molten metal in its immediate zone morequickly than the surrounding metal, with the result that the moltenmetal becomes pasty and more or less quiescent in the zone of the plate,in a relatively short time. Consequently, the upward flow of asubstantial part of the particles ofabrasive material 18 is restricted,since these particles are caught in the zone of pasty metal.

However, a certain proportion of the particles of abrasive material 18will rise upwardly a substantial distance before the molten metal in thezone of the plate 17 becomes sufficiently pasty to restrict the upwardflow of those particles.

Likewise, a certain proportion of the par-v ticles of abrasive material18 will rise toward the plate 17 but a'substantial portion thereof willbe retained at the bottom of the mold cavity until the iron becomessufliciently pasty to restrict their upward flow. Thus the molten metalbecomes intermingled with the abrasive or low specific gravity material.

As aforesaid, the character and thicknes of the plate 17 is such that itbecomes substantially entirely fused and merged with the body of thecasting by the time the same has become chilled.

The casting 25, shown in cross section Fig. 3, is produced by theimproved method using a. single plate 17. The segregated zone 26 ofabrasive material at the outer surface of the casting corresponds inlocation to the bottom surface of the mold cavity, and the segregatedzone 27 of abrasive material corresponds to the relative location of theplate 17.

The density of the zone 27 shades off or i the pouring sprue 15 into themold cavity 12 i material is attained between the segregations thereof.

In use, the zone 26 forms the surface to be presented to wear, and whenthis surface becomes worn off, the metal next encountered o oiferssubstantial resistance to wear due to the bodily incorporateddistributed particles of abrasive material, although somewhat lesswearing resistance than is possessed by the outer skin 26.

lVhen the casting has become further worn off, the zone 27 isencountered which offers relatively high resistance to wear, and themetal beyond that zone still contains suflicient distributed abrasive toofler substantial and sat- 0 isfactory resistance to Wear.

? 'JVGCl plate coated with wear-resistant matcrial immediately adjacentthe bottom surface of the mold cavity before introducing the moltenmetal.

It is to be understood that various modifications may be made incarrying out the invention, without departing from the scope of theappended claims.

We claim:

l. The method of casting products bodily incorporating wear-resistantmaterial, which includes forming a mold for the product to be cast,suspending a fusible medium adhesively coated with comminutedwear-resistant material in the mold, anchoring said adhesively coatedmedium against displacement, and introducing molten metal into the mold.

2. The method of casting products bodily incorporating wear-resistantmaterial, which includes forming a mold for the product to be cast,suspending a perforated metallic plateadhesively coated with comminutedwear-resistant material in the mold, anchoring said adhesively coatedplate against displacement, and introducing molten metal into the mold.

3. The method of casting products bodily incorporating low specificgravity material, which includes forming a mold for the prodnot to becast, adhesively coating the bottom of the mold cavity with comminutedlow specific gravity material, anchoring a. fusible medium adhesivelycoated with comminuted low specific gravity material in the mold cavityin spaced relation to the bottom thereof, and introducing molten metalinto the mold cavity.

4.- The method of casting products bodily incorporating wear-resistantmaterial, which includes forming a mold for the product to becast,.adhesively coating thebottom of the mold cavity with comminutedwear-resistant material, suspending a fusible plate adhesively coatedwith comminuted wear-resistant material in the mold cavity, anchoringsaid plate against displacement, and introducing molten metal into, themold cavity.

5. The method of casting products bodily incorporating differentmaterials, which includes coating a fusible medium with comminutedmaterial of relatively low specific gravity, positioning the coatedfusible medium in a mold cavity and spaced from the walls thereof, andintroducing molten metal into the mold cavity.

6. The method of casting products bodily incorporating differentmaterials, which includes coating a fusible medium with comminutedmaterial of relatively low specific gravity, positioning the coatedfusible medium in a mold cavity'and spaced from the walls thereof, andintroducing molten metal under the coated fusible medium in the moldcavity.

7. The method of casting products bodily incorporating difierentmaterials, which includes coating a fusible medium with comminutedmaterial of relatively low specific gravity, placing the coated mediumin a mold cavity, and intermingling molten metal with the low specificgravity material in the mold cavity.

In testimony that we claim the above, we

have hereunto subscribed our names.

DONALD S. CONNELLY. THEODORE J. HAHN.

